The present disclosure relates to sonar device and methods detection of underwater objects.
Fish finding sonar devices typically employ a single, dual-frequency transducer for sonar detection, where the higher frequency is used for clarity in shallower waters, and the lower frequency is employed to achieve penetration in deeper waters. The lower frequency casts a powerful, wide beam that can more easily detect underwater objects at or near the bottom of a body of water, however, with the beam being relatively wide, the increased depth penetration comes at the expense of lateral spatial resolution. The higher frequency beam, although being incapable of deep penetration, provides a much narrower beam to better detect structural changes and suspended fish. A user may switch between the two frequencies depending on the environment they are in. A common frequency pairing for a low-cost fish finder is 50/200 kHz, where the 50 kHz signal would have a relatively wide angle (40+ degrees) capable of deep penetration with the higher 200 kHz signal having a much narrower beam (˜20 degrees) that is only effective in shallower waters.